SNR (Digital Demod)

SNR (MER) - Signal to Noise Ratio (Modulation Error Ratio) is reported for QAM, DVB QAM, 8PSK, QPSK, APSK, and VSB demodulation formats. SNR is calculated as the ratio of average symbol power to noise power. Noise power includes anything that causes the symbol to deviate from the ideal state position, including additive noise, distortion, and ISI Inter-Symbol Interference: An interference effect where energy from prior symbols in a bit stream is present in later symbols. ISI is normally caused by filtering of the data streams. (inter-symbol-interference). The following formula shows how SNR Signal-to-Noise Ratio is computed:

 

VSB modulated signals